Sioux warriors seize part of Badlands National Park

This is news to me, but apparently for over two years a group of Sioux have been occupying part of Badlands National Park.

According to Backpacker Magazine:

A band of armed Sioux warriors have seized 134,000 acres of Badlands National Park to protect what they say is a sacred burial ground...

This local article attempts to downplay the Backpacker article.

See also this and this.